Designing a PC for Outdoor Storage

I hope to keep a PC permanently installed in the observatory to speed setup, and avoid any more incidents where I drop and break my laptop when cold and stupid.

A PC stored in the observatory would be sheltered from rain, but would go through temperature and humidity extremes. I would think there could be trouble from

• Starting it up when it has been sitting cold in the winter – possibly at temperatures as low as -15 to -20°C. Moving parts will be tight, lubricants will be viscous, etc.
• Shutting it down in the cold after it has warmed up. Will the cooling parts become damp with condensation, and what will such moisture do?
• Performance of LCD monitor in the cold (I know from other appliances that LCD displays fade in the cold).
• Infiltration of insects into parts.

I’m going to try to design a PC that can work in these conditions, and will keep a diary of the attempt here.